如何向自定义画布按钮添加单击和拖动功能？

Question

我用tkinter和canvas做了一个简单的正方形网格，每个正方形都像一个按钮。我现在有它，所以每次你点击一个按钮，它会改变自己的颜色。它在四种颜色和白色之间循环，表示未选择。我想知道如何绑定不仅点击，但点击和拖动。这样用户就可以单击一个正方形，在按住的同时，将光标拖动到要按的其他正方形上

我原以为它可以与<B1-Motion>事件一起工作，但我发现这只会导致最初单击的按钮在其颜色之间循环

这是我的密码：

import Tkinter as tk

class FreeformFrame(tk.Toplevel):
    """ The FreeformFrame class creates a window for the selection of exact droplet placement for printing. """
    def __init__(self, parent, master=None, **settings):
        tk.Toplevel.__init__(self, parent)
        self.parent = parent # parent widget
        if master == None:
            self.master = parent
        else:
            self.master = master
        # ============ IMPORTED VARIABLES =========== #
        # TEST PARAMETERS
        self.res = 200 # microns
        self.dim_x = 10 # mm
        self.dim_y = 10 # mm
        self.c_offset = 30      # Px - Adds some spacing between the edge of the canvas and where items are draw
        self.text_offset = 8    # Px - Adds some spacing beween the edge of the canvas and where text is placed
        # ===================== WINDOW VARIABLES ===================== #
        self.tags_list = []     # Could be used later to target specific shapes drawn to the canvas
        # ========= FRAME PARAMETERS ========= #
        self.name = "Freeform Selection"                    # Text that appears at the top of the window
        self.w_width = 700                                      # Pixel width of main Tk window
        self.w_height = 700                                     # Pixel height of main Tk window
        self.w_center_x = self.w_width/2                    # px coordinate (x) of center of window
        self.w_center_y = self.w_height/2                   # px coordinate (y) of center of window
        self.w_x_offset = 100# (self.master.scr_width-self.w_width)/2   # Pixel x offset for the Tk window.
        self.w_y_offset = 100# (self.master.scr_height-self.w_height)/2 # Pixel y offset for the Tk window.
        # ========== CHANNEL BUTTON SPACING ========== #
        self.buttons_x = int(math.ceil(1000.*self.dim_x/(self.res)))
        self.buttons_y = int(math.ceil(1000.*self.dim_y/(self.res)))
        self.select = []

        # ==================== CLASS INITIALIZATION ==================== #
        # ========== TOPLEVEL WINDOW =========== #
        self.wm_title(self.name)
        self.geometry("%dx%d+%d+%d" % (self.w_width, self.w_height, self.w_x_offset, self.w_y_offset))
        self.resizable(width=False,height=False)

        # ========== CANVAS CONFIGURATION ========== #
        # Start CanvasWell a.k.a. tk.Canvas in disguise preconfigured with buttons for selection
        self.freeform_space = FreeformCanvas(self,self.master)
        self.freeform_space.pack(fill="both", expand=True)

        # Draw channel buttons
        for col in range(self.buttons_x):
            for row in range(self.buttons_y):
                self.channel_button = ChannelButton(self.freeform_space,col,row)


class FreeformCanvas(tk.Canvas):
    """ The FreeformCanvas represents the freeform selection space """
    def __init__(self, parent, master=None, **kwargs):
        tk.Canvas.__init__(self, parent, **kwargs)
        self.parent = parent # parent widget
        if master == None:
            self.master = parent
        else:
            self.master = master
        # ========== CANVAS PARAMETERS ========== #
        self.c_offset = parent.c_offset     # Adds some spacing between the edge of the canvas and where items are draw
        self.text_offset = parent.text_offset   # Adds some spacing beween the edge of the canvas and where text is placed
        # Delimints the draw area
        self.bbox = [self.c_offset, self.c_offset, self.parent.w_width-self.c_offset, self.parent.w_height-self.c_offset]
        self.center_x = self.parent.w_center_x
        self.center_y = self.parent.w_center_y
        self.start_x = self.c_offset
        self.start_y = self.c_offset

        # TEST PARAMETERS
        self.res = parent.res # microns
        self.dim_x = parent.dim_x # mm
        self.dim_y = parent.dim_y # mm

        # Calculate the pixel scale
        self.px_per_mm = (self.bbox[2]-self.bbox[0])/(self.dim_x) # pixels per mm
        self.mm_per_px = self.px_per_mm **-1
        # Label placement
        self.label_coord = [self.text_offset, self.text_offset]
        # XY display placement
        self.xy_label_coord = [self.parent.w_width-self.text_offset, self.parent.w_height-self.text_offset]

        # ========== CANVAS WELL INITIALIZATION ========== #
        self.config(bg=PLATE_BG, width=self.parent.w_width, height=self.parent.w_height, highlightthickness=0, borderwidth=0)
        self.bind("<Motion>", self.show_coordinates)
        # Draw label for build type
        self.label = self.create_text(self.label_coord, text="Freeform Selection", anchor="nw", fill=TEXT_PREVIEW_COLOR)
        # Draw coordinate display
        self.xy_label = self.create_text(self.xy_label_coord,text="Coord: (X = ? mm, Y = ? mm)", anchor="se", fill=TEXT_PREVIEW_COLOR)

    def show_coordinates(self, event=None):
        x_coord = self.mm_per_px*(event.x-(self.parent.w_width/2.0))
        y_coord = self.mm_per_px*(event.y-(self.parent.w_height/2.0))
        self.itemconfigure(self.xy_label, text="Coord: (X = %.3f mm, Y = %.3f mm)" % (x_coord, y_coord))



class ChannelButton(object):
    def __init__(self, freeform_canvas, x, y):
        super(ChannelButton, self).__init__()
        # ========== IMPORTED VARIABLES ========== #
        self.canvas = freeform_canvas
        self.scale = freeform_canvas.px_per_mm

        # ========= CANVAS BUTTON PARAMETERS ========= #
        self.x = x # x index (column)
        self.y = y # y index (row) 
        self.res = freeform_canvas.res          # in microns
        self.c_offset = freeform_canvas.c_offset
        self.c_width = freeform_canvas.dim_x    
        self.c_height = freeform_canvas.dim_y
        self.name = "Coord%i,%i" % (self.x,self.y)
        self.scale = freeform_canvas.px_per_mm
        self.channel_select = 0 # color
        # Unselected: #FFFFFF (White)
        # Channel 1: #DE0600 (Red)
        # Channel 2: #032F95 (Blue)
        # Channel 3: #09B400 (Green)
        # Channel 4: #FFA100 (Orange)
        # Center-to-center spacing between channel buttons
        self.c_to_c = self.scale*self.res/1000.
        self.center_x = self.c_offset+(self.scale*self.res/2000.)+self.c_to_c*self.x
        self.center_y = self.c_offset+(self.scale*self.res/2000.)+self.c_to_c*self.y
        # Start of bbox
        self.start_x = self.c_offset+self.c_to_c*self.x
        self.start_y = self.c_offset+self.c_to_c*self.y
        # End of bbox
        self.end_x = self.c_offset+(self.scale*self.res/1000.)+self.c_to_c*self.x
        self.end_y = self.c_offset+(self.scale*self.res/1000.)+self.c_to_c*self.y
        # Construct bbox
        self.bbox = self.start_x, self.start_y, self.end_x, self.end_y
        # Draw self
        freeform_canvas.create_rectangle(self.bbox,tags=self.name,fill=UNSELECTED)
        freeform_canvas.tag_bind(self.name,'<Button-1>', lambda event, loc=[self.x,self.y]:self.click_button(event,loc))
        freeform_canvas.tag_bind(self.name,'<B1-Motion>', lambda event, loc=[self.x,self.y]:self.click_button(event,loc))

    def click_button(self, event, loc):
        x = loc[0]
        y = loc[1]
        print self.name
        self.channel_select += 1
        self.channel_select = self.channel_select % 5
        if self.channel_select == 0:
            self.canvas.itemconfig("Coord%i,%i"%(x,y),fill=UNSELECTED)
        if self.channel_select == 1:
            self.canvas.itemconfig("Coord%i,%i"%(x,y),fill=CH1)
        if self.channel_select == 2:
            self.canvas.itemconfig("Coord%i,%i"%(x,y),fill=CH2)
        if self.channel_select == 3:
            self.canvas.itemconfig("Coord%i,%i"%(x,y),fill=CH3)
        if self.channel_select == 4:
            self.canvas.itemconfig("Coord%i,%i"%(x,y),fill=CH4)


if __name__ == "__main__":

    root = tk.Tk()
    fff = FreeformFrame(root)
    root.mainloop()

谢谢你的意见